Welcome Guest - Sign Up today
Welcome Guest - Sign Up today

Announcement

Collapse
No announcement yet.

1988 125hp Force lower unit woes

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • 1988 125hp Force lower unit woes

    Hello fellow boating enthusiasts! I'm relatively new to the boating world. I bought this 1988 Bayliner Capri from my former boss who told me it's a great running boat. A couple days after I got it home he told me not to mix the Amsoil any leaner than 50-1 because he was mixing 100-1 and burned up the motor and had to have it rebuilt. Since then I had to have the head gasket replaced, apparently his mechanic used formagasket and didn't have the head surface ground. I also noticed the amount of water spitting out was quite a bit less than other motors I watched but didn't give it a lot of thought until the motor shut down on me in the middle of Lake Erie. Luckily it has a circuit breaker that tripped when it got too hot,h before any real damage to the motor.

    To cut to the chase, I'm in the middle of installing a new water pump kit. While doing so decided I should try to figure out and repair the hiccup the reverse gear has, as though it has a broken tooth or something. From what I've read in the service manual I think I will need to hire a good mechanic to do this because the book says the propeller shaft will have to be removed, forward thrust washer removed then reinstall shaft with new reverse gear assembly in order to check propeller shaft end float. Is this true? Can't this be checked without removing shaft and if end float doesn't meet specs of .010-.011 then remove shaft and replace forward thrust washer with one to meet specs? This is over my head as soon as I have to remove the propeller shaft.

  • #2
    The reverse gear is mounted on the prop shaft and can be removed by dismounting the bearing carrier, removing the split locks and then pull out the prop shaft with the reverse gear. This is the only way to see and inspect the reverse gear. There is a u-tube video you might want to see, albeit it's on a newer Mercury but the process is basically the same.

    Comment


    • #3
      Thanks, Jiggs. Do you think I will need to do all that endrun measuring like the book describes if all I need is to replace the reverse gear assembly?

      Comment


      • #4
        I do not think so. This is because the end run is actually set by the shims in the forward gear and the driveshaft pinion gear.

        Comment


        • #5
          Trying to find someone with the tools and a tech to work on the drive will be the hardest part

          The later years 86/87up don't need shim tools to set the drives up.
          The late cases are produced cut to the right size and the shimming is a math problem now.

          What's the Hiccup you describe in the reverse gear?
          Jumping out of gear, or a jerking ?


          Buy American made Cars and Trucks!!!Towing insurance for a boat,a GREAT thing.
          ​Tools to make my life easier: Battery tester, die grinder, temp.gun, compression tester, DVA meter.

          In Scenic , Beautiful San Sebastian by the sea Florida

          88 Bayliner 21CC 2001 Mercury 225 HP EFI

          PLEASE,NO PERSONAL MESSAGES IF THE QUESTION CAN BE ASKED ON THE OPEN FORUM

          Comment


          • #6
            It's a jerking, sounds and feels like it's skipping out of gear for about a tooth or so. After watching all the YouTube videos last night I realize it could possibly be a couple other things besides a broken gear tooth. Maybe linkage not set to the correct length therefore not fully engaging with the catch dog or a severely worn catch dog. Hoping it's the linkage, cheapest and probably easiest to fix. Also, watching those videos helped me realize that pulling the propeller shaft won't be nearly as difficult as the service manual makes it seem.

            What are your thoughts as to what it most likely will be? I'm sure your guess would be much better than mine. Any help would be greatly appreciated.

            Comment


            • #7
              Thanks, Jiggz, that's a load off my mind not to mention a load off the pocket book because I won't need to buy more tools like a dial indicator. With any luck at all I won't need to pull the pinion gear and drive shaft.

              Comment


              • #8
                Originally posted by Sandy-man View Post
                It's a jerking, sounds and feels like it's skipping out of gear for about a tooth or so. After watching all the YouTube videos last night I realize it could possibly be a couple other things besides a broken gear tooth. Maybe linkage not set to the correct length therefore not fully engaging with the catch dog or a severely worn catch dog. Hoping it's the linkage, cheapest and probably easiest to fix. Also, watching those videos helped me realize that pulling the propeller shaft won't be nearly as difficult as the service manual makes it seem.

                What are your thoughts as to what it most likely will be? I'm sure your guess would be much better than mine. Any help would be greatly appreciated.
                If....you haven't bought any parts for it and you're on Canadian side of Lake Erie, there is a guy that will Lower-units away
                working on 1990 force 90 horsepower Engine serial. 17523 Engine model. 906X90B

                Comment


                • #9
                  If it's jerking, is it constant? Obviously, you are talking about the reverse gear, so this should only be happening when you go in reverse. But going in reverse you should only be going very slow maybe no more than 1500~2000 rpm. So is it constant even only when in idle, in reverse gear? If it is, then maybe it's a broken gear teeth.

                  But if it's not constant and most importantly only happens when you go above idle, then most likely it is a slipping clutch which you can try fixing first by adjusting the upper shift rod.

                  If you already have the LU off, you can also try diagnosing the problem. With the LU clamp vertically on a bench, pull up the shift rod all the way to place it in reverse. With one hand, hold the driveshaft to put a little resistance (still allowing it to turn) while the other hand turns the prop counter clockwise (CCW). If there is a missing tooth or teeth in the reverse gear you will feel a slip when it passes thru the pinion gear of the driveshaft.

                  Comment


                  • #10
                    It's difficult to describe but sounds like a clunking noise and you can feel it like someone is hitting the LU with a hammer with approx each revolution. Yes, only in reverse and usually very slowly backing away from the dock. One day coming back in from fishing and approaching the only open slot on the docks, happened to be on the downwind side with at least 20 mph wind. I had to make several runs at it because the wind kept pushing it too far away from the dock, had to keep backing out quickly to avoid bumping a boat on the next dock. What a pain that was, finally gave up and moved back out and waited for a n opening on the upwind side. Each time backing out the clunking was loud and could really feel it hard, because of increased motor speed.

                    Embarrassing to say the least. Lol This was like my 2nd or 3rd time out on this big of a boat. All the nice looking newer boats at the docks and here comes this rookie in an old beater trying to run with the big dogs. I laugh about it now looking back at that moment. 😂 Now I'm a seasoned old pro, been out at least 10 times in the past 3 years, Lol. If I can get this and a couple other problems fixed I will be out there much more.

                    I have the LU off and mostly taken apart now, only have a couple hours in the morning to work on it each day. But I should be able to have the propeller shaft out before going to work tomorrow afternoon. Once I get it out I will report back what I've found complete with pics if I find any damages.

                    Comment


                    • #11
                      Like I said, you can still test if there's a broken gear teeth in the reverse by engaging the shift rod in reverse and slowly turning the prop while putting on a little resistance on the drive shaft. Anyways, keep us posted of your findings.

                      Comment


                      • #12
                        That sounds like the linkage is not engaging the dog/gear.
                        The dog by now might need resurfacing?
                        Can be done with a dremel.

                        Pics???


                        Buy American made Cars and Trucks!!!Towing insurance for a boat,a GREAT thing.
                        ​Tools to make my life easier: Battery tester, die grinder, temp.gun, compression tester, DVA meter.

                        In Scenic , Beautiful San Sebastian by the sea Florida

                        88 Bayliner 21CC 2001 Mercury 225 HP EFI

                        PLEASE,NO PERSONAL MESSAGES IF THE QUESTION CAN BE ASKED ON THE OPEN FORUM

                        Comment


                        • #13
                          I pulled the shaft out and found no broken or worn gear teeth, clutch dog or whatever it's called doesn't appear to be worn hardly at all. Now I believe all my problems were in the linkage. Not enough pressure on the shift shaft to keep it in gear solidly? I will try to post pics I took.

                          Comment


                          • #14
                            Before I pulled the shaft I did the test as you described, Jiggz, and there was no indication of broken teeth.

                            Comment


                            • #15
                              Sign up today
                              Originally posted by may the force be with you View Post

                              If....you haven't bought any parts for it and you're on Canadian side of Lake Erie, there is a guy that will Lower-units away
                              Nope, I'm on the Michigan side so will likely be ordering any parts from either this site or Marine engines.com

                              Comment

                              Working...
                              X